Adsorption of vapors on model nonporous adsorbents with a physically modified surface

Berezkina, Yu. F.; Dubinin, M. M.; Sarakhov, A. I.

doi:10.1007/bf00912530

Cited by 6 publications

(4 citation statements)

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“…The constant C of the BET equation, which is related to the characteristic adsorption energy in the first monolayer, was determined to be C C60 (N 2 ) = 60 and C C60/C70 (N 2 ) = 85 in the case of nitrogen and C C60 (Ar) = 30 and C C60/C70 (Ar) = 70 in the case of argon. This characterizes both bf samples as weaker than gcb ( C gcb (N 2 ) = 150, C gcb (Ar) = 320, estimated from experimental data 13 ). The C 60 and C 60 /C 70 monolayer capacities n m determined from the above fits were 0.010 and 0.117 mmol/g in the case of nitrogen and 0.0116 and 0.124 mmol/g in the case of argon.…”

Section: Resultsmentioning

confidence: 92%

Nitrogen and Argon Adsorption and SEM Characterization of C₆₀ and C₆₀/C₇₀ Fullerenes: Comparison with Graphite

et al. 1999

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The surface and pore structure properties of the C60 and C60/C70 fullerene powders were studied by means of scanning electron microscopy, helium pycnometry, and 77.4 K nitrogen and argon adsorption. The pore structure of fullerene powders is macroporous and consists mainly of the voids between the fullerene aggregates. In the major part of the adsorption monolayer, both nitrogen and argon interactions with fullerenes are weaker than with graphite, possibly because of the reduction of the gas molecule−mirror image effect in the case of fullerenes. In Henry's law limit, however, nitrogen and argon adsorption on fullerenes is quantitatively similar to that on graphite because of the adsorption potential enhancement in the spaces between the surface fullerene molecules. In the multilayer regime, nitrogen adsorption on both fullerenes becomes similar to that on graphite. Both fullerenes behave similarly with respect to the adsorption of the studied gases.

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Section: Resultsmentioning

confidence: 92%

Nitrogen and Argon Adsorption and SEM Characterization of C₆₀ and C₆₀/C₇₀ Fullerenes: Comparison with Graphite

et al. 1999

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“…Many other experimental adsorption studies of simple gas adsorption on GTCB have been reported, amongst which may be mentioned those of Isirikyan and Kiselev (1962);Sarakhov et al (1961Sarakhov et al ( , 1963; Berezkina et al (1969); Kruk et al (1999);and Gardner et al (2000) who have also reproduced experimental results by simulation and density functional calculations.…”

Section: Argon and Nitrogen On Graphitementioning

confidence: 96%

“…This demonstrates that argon and nitrogen adsorb predominantly on the basal plane, and that water adsorbs predominantly on the functional groups and/or strong sites such as defects grafted at the unsaturated locations at the edges of the graphene layers. Adsorption of argon on a carbon black graphitized at 3000 C pre-loaded with water whose amount is equivalent to 0% and 60% of the monolayer coverage of water (data taken from Berezkina et al, 1969) To substantiate this argument, we show in Figure 6 the Henry constant as a function of temperature for various adsobates on the basal plane (Figures 6a, b) and on a single carboxylic functional group (Figure 6c). At 87K for example, the theoretical Henry constant for argon on the basal plane is 1.2×10 4 nm (eq.…”

Section: Argon and Nitrogen On Graphitementioning

confidence: 99%

The interplay between molecular layering and clustering in adsorption of gases on graphitized thermal carbon black – Spill-over phenomenon and the important role of strong sites

Tan

Zeng

et al. 2015

Journal of Colloid and Interface Science

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We analyse in detail our experimental data, our simulation results and data from the literature, for the adsorption of argon, nitrogen, carbon dioxide, methanol, ammonia and water on graphitized carbon black (GTCB), and show that there are two mechanisms of adsorption at play, and that their interplay governs how different gases adsorb on the surface by either: (1) molecular layering on the basal plane or (2) clustering around very strong sites on the adsorbate whose affinity is much greater than that of the basal plane or the functional groups. Depending on the concentration of the very strong sites or the functional groups, the temperature and the relative strength of the three interactions, (a) fluid-strong sites (fine crevices and functional group) (F-SS), (b) fluid-basal plane (FB) and (c) fluid-fluid (FF), the uptake of adsorbate tends to be dominated by one mechanism. However, there are conditions (temperature and adsorbate) where two mechanisms can both govern the uptake. For simple gases, like argon, nitrogen and carbon dioxide, adsorption proceeds by molecular layering on the basal plane of graphene, but for water which represents an extreme case of a polar molecule, clustering around the strong sites or the functional groups at the edges of the graphene layers is the major mechanism of adsorption and there is little or no adsorption on the basal planes because the F-SS and FF interactions are far stronger than the FB interaction. For adsorptives with lower polarity, exemplified by methanol or ammonia, the adsorption mechanism switches from clustering to layering in the order: ammonia, methanol; and we suggest that the bridging between these two mechanisms is a molecular spill-over phenomenon, which has not been previously proposed in the literature in the context of physical adsorption.

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“…Το αρνητικό πρόσημο υποδηλώνει την ελκτική φύση των δυνάμεων, ενώ οι σταθερές Ci, C 2 , C 3 , καλούνται συντελεστές διασποράς, (dispersion coefficients) και συνδέονται κατ' αντιστοιχία με αλληλεπιδράσεις δίττολου-δίττολου, δίπολου-τετράπολου και τετράπολουτετράπολου. Εξαιτίας της ασάφειας και των προσεγγίσεων που λαμβάνουν χώρα κατά την αριθμητική εφαρμογή της ανώτερης έκφρασης, οι όροι, Γ 8 και r 10 , θεωρούνται αμελητέοι και η παραπάνω εξίσωση Ε 4 απλοποιείται στην ακόλουθη: Σχήμα 2. Μεταβολή της δυναμικής ενέργειας ε(ή, δύο ατόμων σε συνάρτηση με την απόσταση μεταξύ των κέντρων τους.…”

Section: ελκτικές δυνάμεις διασποράς και απωστικές δυνάμεις μικρής εμβέλειας (Dispersion-short Range Repulsive Forces)unclassified

Βαρυμετρική Και Ογκομετρική Μελέτη Ρόφησης Μίγματος Των Αερίων Από Κεραμικές Κόνεις Και Μεμβράνες Καθώς Και Χαρακτηρισμός Της Πορώδους Δομής Τους

Ρωμανός¹

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Κριτική μελέτη των θεωριών που εξηγούν τον σχηματισμό Βοριοττυριτικών πορωδών υ άλω ν, με βάση171 τα πειραματικά αποτελέσματα. Υαλώδης μετάπτωσηΒοριοπυριτικών δομών. 171 5.1.1. Υαλώδης μετάπτωση σε σχέση με π] σύσταση και το 171-172 μέγεθος των περιοχών της δομής. 5.1.2. Ημιεμπειρική εκτίμηση π)ς ταπείνωσης τουΤ 9 σε σχέση με 172-174 το μέγεθος. 5.1.3. Κριτική επί των θεωριών (SD) και (NG) με βάση τον 175 υπολογισμό του Tg. 5.2. Μηχανισμοί διαχωρισμού (NG). 176 5.2.1. Διαχωρισμοί (NG) και σημείο υαλώδους μετάπτωσης. 176-177 5.2.2. Έλεγχος της θεωρίας του Haller. 178-180 5.2.3. Συνένωση των περιοχών (NG) -θεωρία του Seward. 180-182 5.3. Μηχανισμοί διαχωρισμού (SD). 183 5.3.1. Οι απόψεις των Cahn-Charles. 183 5.3.2. Επίδραση π)ς Υαλώδους μετάπτωσης στους 1g3 1g5 μετασχηματισμούς φάσεων. 5.3.3. Επίδραση του Τ" στον διαχωρισμό φάσεων πολλών 185 _ 1 g6 βημάτων. 5.3.4. Μια δεύτερη εκδοχή του διαχωρισμού σε δύο βήματα. 186-187 5.4. Ταξινόμηση των δομών ανάλογα με το μέσον διαλυτοποίησης. 5.4.1. Αποτελέσματα για τα δείγματα των 600°C. 188-189 5.4.2. Αποτελέσματα για τα δείγματα των 580°C. 189 5.4.3. Αποτελέσματα για τα δείγματα των 630°C. 190 5.5. Συνοπτική εικόνα για την εξέλιξη της δομής στο υλικό Vycor®.

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Adsorption of vapors on model nonporous adsorbents with a physically modified surface

Cited by 6 publications

References 2 publications

Nitrogen and Argon Adsorption and SEM Characterization of C₆₀ and C₆₀/C₇₀ Fullerenes: Comparison with Graphite

Nitrogen and Argon Adsorption and SEM Characterization of C₆₀ and C₆₀/C₇₀ Fullerenes: Comparison with Graphite

The interplay between molecular layering and clustering in adsorption of gases on graphitized thermal carbon black – Spill-over phenomenon and the important role of strong sites

Βαρυμετρική Και Ογκομετρική Μελέτη Ρόφησης Μίγματος Των Αερίων Από Κεραμικές Κόνεις Και Μεμβράνες Καθώς Και Χαρακτηρισμός Της Πορώδους Δομής Τους

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Adsorption of vapors on model nonporous adsorbents with a physically modified surface

Cited by 6 publications

References 2 publications

Nitrogen and Argon Adsorption and SEM Characterization of C60 and C60/C70 Fullerenes: Comparison with Graphite

Nitrogen and Argon Adsorption and SEM Characterization of C60 and C60/C70 Fullerenes: Comparison with Graphite

The interplay between molecular layering and clustering in adsorption of gases on graphitized thermal carbon black – Spill-over phenomenon and the important role of strong sites

Βαρυμετρική Και Ογκομετρική Μελέτη Ρόφησης Μίγματος Των Αερίων Από Κεραμικές Κόνεις Και Μεμβράνες Καθώς Και Χαρακτηρισμός Της Πορώδους Δομής Τους

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Nitrogen and Argon Adsorption and SEM Characterization of C₆₀ and C₆₀/C₇₀ Fullerenes: Comparison with Graphite

Nitrogen and Argon Adsorption and SEM Characterization of C₆₀ and C₆₀/C₇₀ Fullerenes: Comparison with Graphite